strength, formation mechanisms, and mimetics. An understanding of the real
hierarchically organized structure in biominerals is required to advance to the
next stage of chemistry, biology, and materials science.
6.2.1 Carp Otolith
Fish otolith is a kind of typical natural calcium carbonate biomineral, which is
composed of a pair of lapillus, sagitta, and asteriscus, respectively, as shown in
Fig. 6.2. Otoliths are involved in the perception of sound and the maintenance of
postural equilibrium in fishes. Although the relationship between microstructure
and the growth history of fish otolith is widely known, the hierarchical structure of
the otolith, especially at the nanometer level is not well understood. Li et al. (2009)
observed the nanometer scale morphology of the otoliths and investigated the
hierarchical levels of organization in wild carps otoliths in order to have a better
understanding of the otolith structure–ecology relations. Investigation on the otolith
hierarchical structure plays a key role in the study of the hydro environmental
chemistry and calcium carbonate biomineralization.
6.2.1.1 Hierarchical Structure of Lapillus
Lapillus, which is composed of aragonite, is a type of mineralized material with
highly complex hierarchical structure. The other major component in the lapillus is
protein which accounts for 4–5% in weight. The structure of lapillus can be
separated into seven levels.
Level 1: the aragonite nanocrystals
The basic mineral structure unit of lapillus is nanometer-scale aragonite crystal
(Fig. 6.6a), the (111) and (002) planes are labeled. The aragonite nanocrystals build
the first level of the lapillus minerals.
Level 2: the aragonite fibrils
The aragonite nanocrystals grow along the c-axis (the black arrow in Fig. 6.6b)
and form a nanofibril structure with a diameter of 60 nm. The aragonite fibrils are
covered by the proteins.
Level 3: fibril arrays
In the lapillus, mineral fibrils are present in arrays aligned along their diameter.
The fibrils are intimately associated and the banding patterns in neighboring fibrils
are in connection with each other (Fig. 6.6c). The fibril array is clearly highly
ordered in two dimensions and forms the layered structure. All the different layers
accumulate compactly and parallel to each other. The black arrow shown in
Fig. 6.6c shows the array direction of the fibrils which is perpendicular to the
long axes of the fibrils.
Level 4: three-dimensional stick
154
Q. Feng
hierarchically organized structure in biominerals is required to advance to the
next stage of chemistry, biology, and materials science.
6.2.1 Carp Otolith
Fish otolith is a kind of typical natural calcium carbonate biomineral, which is
composed of a pair of lapillus, sagitta, and asteriscus, respectively, as shown in
Fig. 6.2. Otoliths are involved in the perception of sound and the maintenance of
postural equilibrium in fishes. Although the relationship between microstructure
and the growth history of fish otolith is widely known, the hierarchical structure of
the otolith, especially at the nanometer level is not well understood. Li et al. (2009)
observed the nanometer scale morphology of the otoliths and investigated the
hierarchical levels of organization in wild carps otoliths in order to have a better
understanding of the otolith structure–ecology relations. Investigation on the otolith
hierarchical structure plays a key role in the study of the hydro environmental
chemistry and calcium carbonate biomineralization.
6.2.1.1 Hierarchical Structure of Lapillus
Lapillus, which is composed of aragonite, is a type of mineralized material with
highly complex hierarchical structure. The other major component in the lapillus is
protein which accounts for 4–5% in weight. The structure of lapillus can be
separated into seven levels.
Level 1: the aragonite nanocrystals
The basic mineral structure unit of lapillus is nanometer-scale aragonite crystal
(Fig. 6.6a), the (111) and (002) planes are labeled. The aragonite nanocrystals build
the first level of the lapillus minerals.
Level 2: the aragonite fibrils
The aragonite nanocrystals grow along the c-axis (the black arrow in Fig. 6.6b)
and form a nanofibril structure with a diameter of 60 nm. The aragonite fibrils are
covered by the proteins.
Level 3: fibril arrays
In the lapillus, mineral fibrils are present in arrays aligned along their diameter.
The fibrils are intimately associated and the banding patterns in neighboring fibrils
are in connection with each other (Fig. 6.6c). The fibril array is clearly highly
ordered in two dimensions and forms the layered structure. All the different layers
accumulate compactly and parallel to each other. The black arrow shown in
Fig. 6.6c shows the array direction of the fibrils which is perpendicular to the
long axes of the fibrils.
Level 4: three-dimensional stick
154
Q. Feng